[willamette-fcst] Forecast - Friday, February 13th, 2009
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Fri Feb 13 09:07:27 PST 2009
Daily Smoke Management Forecast
Oregon Department of Agriculture
Smoke Management Program
Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts.
Friday, February 13th, 2009 at 9:00am.
Agricultural burning is allowed. Suggested burn times are from now until 3:30pm.
Stack burning is not allowed.
Light rain moved onshore and into the western valleys
Thursday night and was already tapering off this morning.
Rainfall amounts were around one-tenth of an inch or less,
with the bulk of the moisture from this latest weather
system moving south of the region, into California. Cloudy
skies and areas of light rain kept valley temperatures above
freezing overnight with most minimums in the mid 30s.
The air mass is still quite cold over Oregon. The freezing
levels over Salem and Medford were measured at just 2100 and
1900 feet respectively early this morning. That puts the
snow level near 1000 feet this morning. ODOT road cameras
showed mostly wet pavement over the coastal mountain passes,
although packed snow was reported over Sunset Summit, on HWY
26. The Cascade and Siskiyou paseses were snow-packed, with
new snow amounts ranging from less than an inch on Mt. Hood
up to about 4 inches over sections of the southern Cascades
The ODA surface analysis put the low-pressure center about
100-150 miles off the southern Oregon/northern California
coast, with northeasterly pressure gradients across western
Oregon. As the low-pressure center continues to drift
southeastward, pressure gradients will slowly turn more
northerly across western Oregon this afternoon. Transport
wind directions are not conducive to good valley ventilation
for stack burning, so it is not allowed today.
Skies should remain mostly cloudy today, with satellite
imagery showing an impressive cloud-shield circulating
around the low-pressure center across all of oregon.
However, showers will continue to taper off, with the main
jet stream energy focused well south of the region. The
low-pressure center will weaken and move inland, into
northern California, tonight. Partial clearing overnight
may allow Willamette Valley temperatures to locally drop
below freezing. There will still be a slight chance of a
light shower with the snow level at or below 1000 feet.
N 5-10 this morning, N 5-10 this afternoon.
NE 8 this morning, NNE 10 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 2000 feet. Ventilation index 20.
Salem\'s high temperature today will be near 44.
Minimum relative humidity will be near 62%.
Salem sunset tonight: 5:38pm; sunrise tomorrow: 7:14am.
A split-flow jet stream pattern is forecast this weekend
through much of next week. The southern branch of the jet
stream, and main moisture feed, will continue to be directed
into California. A weak upper-level trough will maintain
partly to mostly cloudy skies, cool temperatures and at
least a few showers over Oregon...mainly south. Snow levels
will rise a little but remain below the Cascade passes.
Willamette Valley temperatures should remain slightly below normal.
Tomorrow (14 Feb): Mostly Cloudy. Slight Chance of a Shower. Snow Level 1500 Feet. 30/46
Sun (15 Feb): Chance of Showers and Cool. Snow Level Near 2000 Feet. 32/46
Mon (16 Feb): Mostly Cloudy. Slight Chance of Showers. Snow Level 2500 feet. 32/48
Tue (17 Feb): Chance of Showers. Snow Level 2-3000 Feet. 33/48
Wed (18 Feb): Slight Chance of Showers. Snow Level 3000 Feet. 33/50
Thu (19 Feb): Partly Cloudy. Slight Chance of Showers. 33/51
Fri (20 Feb): Partly Cloudy. Increasing Chance of Showers Late. 33/52
weather at oda.state.or.us
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